DNA Structure and Function

Question 1

Nucleotide Comp

Answer 1

5’ sugar, phosphate group (phosphodiester in between nucleoside to sugar) glycosidic bonds, (sugar to base)

Question 2

Purines/Pyriminadines

Answer 2

AG/TCU

Question 3

Methylation

Answer 3

Inactivation-used for making live vaccines with a particular enzyme methylated

Question 4

Nucleoside analog

Answer 4

Missing 3’OH no replication, look like real nucleoside so cell well incorporate them

Question 5

Nucleic acid

Answer 5

polymer of nucleotides

Question 6

Nuc Polymerization

Answer 6

Empty 5’ and 3’, 3’ phosphodiester bond to Phosphate group connected to 5’-DRAW

Question 7

exo vs endo nuclease

Answer 7

Cuts at end of chain, cleave internal phosphodiester bonds-site specific cleavage

Question 8

B form DNA traits

Answer 8

Antiparallel, right hand, 10 bases per turn, major and minor grooves, complete helix turn every 34Angstroms

Question 9

H bonding

Answer 9

AT=2bonds, Gc=3 bonds, AT easier to break

Question 10

Chargaffs Rule

Answer 10

Same amount of purines as pyramidines

Question 11

Relaxed DNA

Answer 11

linear or circularized B-form

Question 12

Negative Supercoil traits, formation, and stabilization

Answer 12

Fewer helical turns (energy favorable), created by partially unwinding helix then resoring interactions-stabilized by histones

Question 13

Topoisomerases+ How they work

Answer 13

Introduce swivel points, restores proper coiling when inporper detected (work ahead and behind rep fork)
-Ligase/nuclease activity-break strand or strands, pass them or it through break, rejoin

Question 14

Top I vs Top II

Answer 14

1 strand break vs 2 strand break

Question 15

Bacterial DNA gyrase

Answer 15

Req ATP, remove positive or negative supercoils, facilitates bacterial rep, can introduce negative supercoils, good anti bacterial

Question 16

Inhibit Euk Top

Answer 16

result in cell death-an convert to DNA breaking agent

Question 17

DNA in proks

Answer 17

stored in nuceloid region, associate with non histone proteins

Question 18

DNA in euks

Answer 18

Associated with histoones +other proteins, in nucleus, nutleoprotein complex is chromatin

Question 19

Chromatin

Answer 19

Histones are small basic proteins (arg/lys rich), histone h1 between nucleosome cores-called DNA spacer-promotes tight packing of chromosomes

Question 20

Nucleosome structure

Answer 20

Histone optimer (2 each type), 1 and 3/4 turn in negative directionaround nucleosome

Question 21

Euk Dna hierarchy

Answer 21

Chromatin, Nucleosomes, Solenoids, Loops around protein scaffold (compacted beads on string), loops radiaiting outside of scaffold